1. Field of the Invention
The present invention relates to a method for generating a tensilized tape performance metric.
2. Background Art
Tensilized tape media systems are commonly used to store information due to the reliability, low cost, efficiency, and ease of use of such systems. Information may be stored on tensilized tape (i.e., tape, tape media) through a variety of means such as magnetic, optical, and the like. In general, tensilized tape may be made more cost-effective by increasing the information storage density of the tape, and/or by increasing the rate of data storage and retrieval.
One method of increasing the storage density of a tensilized tape is to include more data tracks and/or servo tracks (i.e., data/servo tracks) across a given width of the tape. However, the increase in density generally requires a narrowing of the data/servo track width, a decrease in the spacing between adjacent data/servo tracks, or both. As data/servo track width and/or spacing decreases, positioning of the tape with respect to a tape read and/or write head (i.e., tape read/write head, tape head) becomes more critical to reduce the possibility of errors introduced while reading and/or writing information. Factors such as tape cartridge (i.e., tape pack, spool, etc.) tension, temperature, humidity, time, and the like may cause the width of tape to shrink or expand. The change in the width of the tape is generally referred to as transverse (i.e., lateral) distortion and may affect the relative position of the data/servo tracks. Because servo tracks are generally written to the tape prior to data tracks, servo track positioning may be particularly prone to distortion.
Another method of increasing the storage density of a tensilized tape in a tape cartridge is to reduce the thickness of the tape. Reducing tape thickness, however, may also result in increased susceptibility to tape distortion.
The rate of data storage and retrieval may be increased by reading and/or writing multiple data/servo tracks simultaneously. If many data/servo tracks are written on a tape, then subsequent tape distortion may cause the multiple readers on a tape head to experience varying degrees of off-track. Accordingly, some of the tape head readers may pick up adjacent track signals. Such cross-reads are generally detrimental to the quality of the read signal and may lead to an unacceptable level of read errors.
Conventionally, a metric is known for a combination of distortions due to temperature and humidity expansion. However, no metric presently exists for combining creep and shrink.
Accordingly, it is desirable to have a method for generating a tensilized tape performance metric such that a tape media may be tuned (i.e., modified, improved) to resist (i.e., limit, reduce) creep and/or shrink distortion. Such a metric may also be implemented to determine a tape's resistance to creep and/or shrink distortion (i.e., generate a creep/shrink quality rating) prior to data recordation.